Compensation of nonlinearlities in transmitters using quadrature modulation

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(11)

EP 0 923 213 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	02.01.2002 Bulletin 2002/01

(43)	Date of publication A2:
	16.06.1999 Bulletin 1999/24

(21)	Application number: 98123292.9

(22)	Date of filing: 07.12.1998

(51)	International Patent Classification (IPC)⁷: H04L 27/36

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

10.12.1997 JP 33967697

(71)	Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
	Kadoma-shi, Osaka 571-8501 (JP)

(72)	Inventors:
	Matsuoka, Akihiko Yokohama 226-0021 (JP) Orihashi, Masayuki Ichikawa-shi, Chiba-ken 272-0001 (JP) Sagawa, Morikazu Inagi-shi, Tokyo 206-0821 (JP)

(74)	Representative: Finsterwald, Martin, Dr. et al
	Manitz, Finsterwald & Partner GbR Martin-Greif-Strasse 1 80336 München 80336 München (DE)

(54)	Compensation of nonlinearlities in transmitters using quadrature modulation

(57) A system for the compensation of distortion due to nonlinearities of a power amplifier has power calculation means for calculating the transmission power from baseband quadrature signals. Two sets of compensation coefficients are derived from the calculated transmission power, the first set designed for compensation of nonlinearities of the quadrature modulator, and the second for the compensation of nonlinearities of the power amplifier. The two sets of coefficients are combined, to arrive at a final set of compensation coefficients, which are then used to modify the baseband quadrature signals.

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